J. Fon and K. Johnson 57 Syllable Onset Intervals as an Indicator of Discourse and Syntactic Boundaries in Taiwan Mandarin* Janice Fon 1 and Keith Johnson 2 1 National Taiwan Normal University, Taiwan 2 The Ohio State University, U.S.A. Authors 57 LANGUAGE AND SPEECH, 2004, 47 (1), 57 – 82 Abstract This study looks at the syllable onset interval (SOI) patterning in Taiwan Mandarin spontaneous speech and its relationship to discourse and syntactic units. Monologs were elicited by asking readers to tell stories depicted in comic strips and were transcribed and segmented into Discourse Segment Units (Grosz & Sidner, 1986), clauses, and phrases. Results showed that the degree of final lengthening was modulated by boundary types. Lengthening before discourse boundaries was longer than that before clausal boundaries, which was in turn longer than that before phrasal boundaries. Final SOI lengthening also seemed to reflect cogni- tive load. At the discourse and clausal levels, the degree of lengthening is modulated by narration order. First narrations tended to have longer final SOIs than second narrations. In addition, there was also a mild length- ening effect in nonfinal SOIs, as was evidenced by the length differences in initial and medial SOIs and the differential lengthening effect regarding the positioning of phrases in a clause. Key words boundary cues hierarchical structure spontaneous speech syllable onset interval Taiwan Mandarin * Acknowledgments: This study is derived from a research project of the first author under the supervision of the second author in the Department of Linguistics, The Ohio State University. Parts of this article were presented at the Brown Bag Series at the Center for Cognitive Sciences, The Ohio State University, and at ICSLP 2000 in Beijing, China. Many thanks go to Dr. Mary Beckman, Dr. Chris Brew, Mr. Martin Jansche and all of our colleagues in the Phonetics Laboratory in the Department of Linguistics, The Ohio State University. Special thanks go to Ms. Laura Hsiu-min Liu for kindly sharing her record- ings with us, Dr. Tammy Miao-Hsia Chang for helping out with the discourse analyses, and Mr. Hsin-fu Chiu for acting as a second labeler. We would also like to thank Mr. Pang- Hung Hsu for the technical support and Dr.Kuenhi Tsai for the statistical analyses. Many thanks also go to the Editor Dr. Marc Swerts and the two reviewers, Dr. Brigitte Zellner Keller and Dr. Anders Eriksson for the invaluable comments. Without them, this paper could not have been finished. Naturally, any faults are ours. Address for correspondence: Janice Fon, Assistant Professor, Department of English, 162 Hoping E. Rd., Sec.1, National Taiwan Normal University, Taipei 106, Taiwan; e-mail: <jfon@cc.ntnu.edu.tw>. Language and Speech ‘Language and Speech’ is ©Kingston Press Ltd. 2004